1) as you level up they use less, so you can still summon at higher levels. Early on in your career you need to eat all 3 eitr foods to use it once your food wears down.

2) ^^^ it uses less after a while.

4) you can shield and harpoon them into a boat or walk into them to shove them a bit.
6) they get stronger with higher skill. They do fine in mistlands at 50+ skill and shielded. You can use your butcher knife/pet killer knife and resummon until you get the pair you want.
7) wait until your BM skill is 50+ to complain here. The if you are unhappy, circle back on it.
9) I agree, the timer could be longer, but the barrier is very powerful at higher BM skill. They maybe don't want you to be immortal.

a lot of this stuff could be better. eg it could normal attack, melee skel, alt attack, ranged one. They could keep up with the player better. They could be less moronic about deer specifically. They could stand a 'stay and guard' vs a 'follow and fight' mode. Maybe we will see some improvements? As they stand, though, they are incredibly awesome at grey dwarf butchery. The #1 most annoying thing when gathering wood or something, they take care of it. They are decent at defending your home in invasions if you play the 'fight the invasion' style (rather than the 'you can't get to me style'). They are possibly OP at max skill, but its hard to say: its a long road to get that high.